SOLUTION: I have theta = x. How do I find the exact value of sin2x when x is an acute angle with cosx = 3/5.

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Question 69494: I have theta = x.
How do I find the exact value of sin2x when x is an acute angle with cosx = 3/5.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
How do I find the exact value of sin2x when x is an acute angle with cosx = 3/5.
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sin2x=2(sinx)(cosx)
You know cosx = 3/5; You need to find sinx.
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Draw a rt. triangle with hyp=5 and side adjacent to angle x is 3
Use Pythagoras to find the side opposite angle x = sqrt(5^2-3^2)=4
The sinx = opp/hyp = 4/5
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Then sin2x = 2(4/5)(3/5)= 24/25
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Cheers,
Stan H.